No. If you missed buying them on Sentinel Island, the only way to get them would be to reload a save before entering the summoning chamber and taking over the battle tower.
In the original release of D2:ED there was a complete ten piece equipment set in each of the fortresses for Stone (Archmage set), Raze (Hunter's set - ranger) and Kali (Scorpion set - warrior). These sets were moved around in DKS (Ulthring's set is still gotten by mindreading those three bosses, as well as Xanlosch in Stone's fortress), and additional sets added.
